#include<iostream>
#include<unistd.h>
#include<string.h>
#include <sys/types.h>
#include <sys/wait.h>

void ChildWrite(int wfd)
{
    int cnt = 0;
    char buffer[1024];
    while(true)
    {
        snprintf(buffer,sizeof(buffer),"I am a child,pid:%d,cnt:%d",getpid(),cnt++);
        write(wfd,buffer,strlen(buffer));
        sleep(1);
    }
}

void FatherRead(int rfd)
{
    char buffer[1024];
    while(true)
    {
        buffer[0] = 0;
        ssize_t n = read(rfd,buffer,sizeof(buffer)-1);
        if(n>0)
        {
            buffer[n] = 0;
            std::cout<<"child say: "<<buffer<<std::endl;
        }
    }
}
int main()
{
    //1.创建管道
    int fds[2]  = {0};
    int n = pipe(fds);
    if(n<0)
    {
        perror("pipe error\n");
        return 1;
    }

   std:: cout<<"fds[0]:"<<fds[0]<<std::endl;
   std:: cout<<"fds[1]:"<<fds[1]<<std::endl;

   //2.创建子进程
   pid_t id = fork();
   if(id==0)
   {
       // child
       // 子进程关闭读端
       close(fds[0]);
       ChildWrite(fds[1]);
       close(fds[1]);
       exit(0);

   }

   //父进程关闭写端
   close(fds[1]);
   FatherRead(fds[0]);
   close(fds[0]);
   waitpid(id,nullptr,0);
   return 0;
}